1. Field of the Invention
The invention relates to an improved structure of inductance core and wire frame, and more particularly, to a core structure that can effectively increase the covering area of the core with respect to the coil, lessen the inductance leakage and improve the efficiency of inductance device.
2. Description of the Prior Art
As shown in FIG. 1, the core (5) of a conventional core structure of the inductance or the transformer appears mainly in E-shape. The core (5) includes a center post (51) and two side posts (53) that are salient in the same direction and disposed at the center and at the ends thereof respectively, as well as recessed portions (52) positioned between the center post (51) and the side posts (53). A wire frame (6), being accommodating the core (5) for assembling into an inductance or a transformer, has a center hole (61) at the center portion thereof. The center hole (61) has a bobbin (62) at the periphery thereof for the winding of a coil (621). Brazing posts (63) having drawing heads (not shown in the Figure) for pulling out the wire (not shown in the Figure) from the coil (621) make the center posts (51) of the two cores (5) insert into the center hole (61) of the wire frame (6). The center posts (51) then contact each other at their ends, and have their recessed portions (52) containing respectively the coils (621) at the periphery of the center hole (61). In the meantime, each of the side posts (53) of the two cores (5) forms a magnetic loop on the inner side of the coil (621) accommodating the center posts (51) at the two outer sides of the coil (621). However, since the covering area of the side posts (53) of the core (5) of the above-mentioned inductance or transformer is rather small, a large portion of the coil (621) of these kinds of structure exposes to the air. This will result in serious inductance leakage of the inductance or the transformer and will hardly improve the magnetic-induction efficiency.
Shown in FIG. 2 and FIG. 3 are relatively progressive structures of the prior art. A center hole (41) having a bobbin (42) at the periphery thereof for the winding of a coil (421) is provided at the center of the wire frame (4) of the structure. Moreover, extended portions (431) are also provided at both ends of the wire frame (4) to connect to the center section of two bus panels (432) having brazing posts (43) of the drawing head (not shown in the Figure) of lead-out coil (421). What is more, a center post (31) provided at the center of the core (3) has a containing channel (32) with side recesses (331) on the two opposite sides thereof. This makes the periphery of the containing channel (32) form two opposite side walls (33). When it comes to assembling, the two cores (3), after the center posts (31) inserting into the center hole (41), contact each other, and the containing channel (32) contains the bobbin (42) of the coil (421). In the meantime, the two extended portions (431) extend out through the side recesses (331) such that the bus panels (432) and the brazing posts (43) maintain at the location outside the core (3). A magnetic loop can be formed at the periphery of the bobbin (421) by the use of the side walls (33) accommodating the center posts (31). However, although this kind of inductance or transformer structure has a relatively large area of core covering as comparing with the above-mentioned prior art, there are still large areas of side recesses (331) that make the coil (421) expose to the air. Therefore, there are still some rooms for improving the magnetic leakage and efficiency for the inductance or the transformer.